An LED-array image printer in accordance with either of the aforementioned applications requires an electronic control system for controlling the position of the photosensitive medium and the activation of the light emitting diodes that make up the scanning LED array.
U.S. Pat. No. 4,739,352 entitled "Electronic Control of Imaging System" discloses and claims a method and apparatus for controlling the activation of diodes in the LED-Fiber Optic Character Printer disclosed in U.S. Pat. No. 4,342,504. The system there disclosed is directed to controlling an array of two staggered rows of light emitting diodes in an LED-fiber optic printer during bi-directional scanning, and includes compensation during reverse scanning for the required tilt angle of the staggered array. The apparatus there disclosed translates raster image scans into parallel bytes of vertical information slices. However, the scanning speed of the foregoing system is limited by the fact that the scanning head must make at least one full scan in each direction across the width of the photosensitive medium before advancing the photosensitive medium. As will be readily appreciated, scanning each and every line in full throughout the entire page length limits the speed at which each page can be scanned In addition, since a slice of information of a preset size must be exposed during every scan, the information to be printed is often split between scans. Thus, accurate registration of each and every scan relative to the preceding and subsequent scan is required.
It is one object of the present invention to provide a system for controlling a high resolution scanning LED-array image printer.
A further object of the present invention is to provide, in a high resolution scanning LED array image printer, a system for controlling printhead position and activation of light emitting diodes in order to increase the speed of the image printer.
Yet a further object of the invention is to provide a control system for an LED-array image printer which reduces the number of split images that occur during scanning of a given page.
These and other highly desirable and unusual results are accomplished by the present invention in a reliable, high speed LED array image printer control system at relatively modest cost.
Objects and advantages of the invention are set forth in part herein and in part will be readily appreciated herefrom, or may be learned by practice with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims.